Differential expression of the Middle East respiratory syndrome coronavirus receptor in the upper respiratory tracts of humans and dromedary camels

Middle East respiratory syndrome coronavirus (MERS-CoV) is not efficiently transmitted between humans, but it is highly prevalent in dromedary camels. Here we report that the MERS-CoV receptor-dipeptidyl peptidase 4 (DPP4)-is expressed in the upper respiratory tract epithelium of camels but not in that of humans. Lack of DPP4 expression may be the primary cause of limited MERS-CoV replication in the human upper respiratory tract and hence restrict transmission.